Where does good come from?
…His new argument, in a nutshell, amounts to a frontal attack on long-accepted ideas about one of the great mysteries of evolution: why one creature would ever help another at its own expense. Natural selection means that the fittest pass down their genes to the next generation, and every organism would seem to have an overwhelming incentive to survive and reproduce. Yet, strangely, self-sacrifice exists in the natural world, even though it would seem to put individual organisms at an evolutionary disadvantage: The squirrel that lets out a cry to warn of a nearby predator is necessarily putting itself in danger. How could genes that lead to such behavior persist in a population over time? It’s a question that bedeviled even Charles Darwin, who considered altruism a serious challenge to his theory of evolution.